1. Field of the Invention
The present invention relates to a method and a structure of connecting devices which need an electrical connection.
2. Description of the Related Art
In the case where connected devices involving an electrical connection are connected, in general, they are electrically connected via a harness after fixing a device to the other device. For example, in the case where an ignition coil is attached to an engine main body of an automobile, an igniter portion of the ignition coil is connected with a distributor via an ignition cable that is a harness, and further the distributor is connected with an ignition plug.
A pair of connectors are employed for the connection between the igniter portion and the ignition cable. The connector of one side is integrally formed with a head portion of the ignition coil containing the igniter portion in a protruding manner. The other connector is connected with the end of the ignition cable extending from the distributor.
After attaching the ignition coil to the engine main body, by inserting the one connector into the other connector, they are electrically connected. Furthermore, liquidtightness inside the connectors is ensured by means of a packing provided in the other connector.
In the device connection method described above, work to connect the pair of connectors is necessary after attaching the ignition coil to the engine main body. Moreover, inspection after the work is necessary with respect to each of the attaching and the connecting of the connectors. Thus, process is complicated, thereby becoming a factor in a rise of manufacturing cost.
Further, in the device connection method, a disadvantage is that there are many electrical contact points. It is necessary to ensure not only regarding the connection between the connectors but also regarding the connection between the connector and the ignition coil and between the connector and the ignition cable. Thus, it becomes necessary to take counter measures for liquid tightness and prevention of falling off for each contact point. Therefore, the number of components becomes large, thereby increasing the possibility of failure as well as raising in a cost of components.
The present invention was made considering the above-described circumstances, and it is an object of the present invention to provide a device connection method by which an electrical connection can be ensured only by connecting devices and the reduction in manufacturing procedure and cost can be achieved.
A first aspect of the present invention provides a connection method of devices which need an electrical connection wherein a first device is provided with a fitting opening for fixedly fitting a second device thereinto and a circuit substrate on which a conductor extended from the periphery of the fitting opening to the inner periphery thereof to be a first terminal is printed, and a second device is provided with a second terminal coming into contact with the first terminal on the outer periphery of a part which is fitted into the fitting opening. The first terminal is folded on the inner periphery of the fitting opening, and when the second device is fitted into the fitting opening, the first terminal and the second terminal are connected electrically.
In this connection method, when the second device is fixedly fitted into the first device, the first terminal of the fitting opening of the first device is connected electrically to the second terminal of the outer periphery of the second device. The printed conductor of the circuit substrate provided on the periphery of the fitting opening of the first device is extended and is folded on the inner periphery of the fitting opening to form and arrange the first terminal, and the second terminal is electrically connected with the printed conductor of the substrate. Accordingly, only by fitting the second device into the first device, an electrical connection becomes possible, and the work is remarkably simplified. Since the folded part to be the first terminal in the substrate is sandwiched between the fitting opening and the second terminal to be fixed, the electrical connection is further stable and reliable. Since a connector is not used, the number of components is reduced.
According to a second aspect of the present invention, there is provided a connection method wherein positioning means for defining the relative position between the first device and the second device is further provided. With this means, a normal electrical contact state between the first terminal and the second terminal can be maintained constantly in the fitting state of the devices, and imperfect contact can be prevented.
According to a third aspect of the present invention, the method according to the first aspect of the invention further comprising the step of inserting an annular seal member surrounding the fitting opening between the circuit substrate and the first device and between the substrate and the second device.